Mathematical knowledge points in the second volume of the second grade of primary school (1 ~ 3 unit)
Unit 1: data collection and arrangement 1. Collect data by drawing the word "positive".
2. Use statistical charts to represent data.
3, according to the statistical chart can make some judgments.
4, data collection-sorting-analysis table.
Unit 2: Division in Table (1)
I. Average score
1, the meaning of average score: divide some projects into several parts, and each part gets the same amount, which is called average score.
2, the average method:
(1) When some articles are divided equally according to the prescribed number of copies, they can be divided into one article or several times until all the articles are finished.
(2) Divide some items into several equal parts. Think about time-sharing: this number can be divided into several such parts.
Second, division.
1. Meaning of the division formula: As long as it is the process of average division, it can be expressed by the division formula.
2. Reading method of division formula: usually read from front to back, ⊙ reading is division, = reading is arithmetic, and other reading methods remain unchanged.
3. Name of each part of the division formula: In the division formula, the number before the division sign is the dividend, the number after the division sign is the divisor, and the number obtained is the quotient.
Third, use the multiplication formula of 2~6 to find the quotient.
1, the method of quotient:
(1) Find the quotient by the average score method.
(2) Use the multiplication formula to find the quotient.
(3) Use the multiplication formula to find the quotient.
2. When you use the multiplication formula to find the quotient, you should multiply the dividend of the divisor.
Fourth, solve the problem.
1, the solution to the average score problem:
Total number/share = number of shares, total number/share = number of shares, dividend = quotient x divisor,
Dividend = quotient × divisor+remainder, divisor = dividend present quotient, factor× factor = product,
One factor = product ÷ another factor
2. The method of solving practical problems by multiplication and division:
(1) The problem to be solved requires finding the total number and calculating by multiplication;
(2) Required questions require finding out the number of copies or the number of copies per copy, and calculating by division.
Unit 3: Graphic Motion (1)
1, axisymmetric figure: folded in half along a straight line, with both sides completely coincident. The figure that can completely overlap after being folded in half is an axisymmetric figure, and the straight line where the crease is located is called the axis of symmetry.
Chinese characters with axisymmetric graphics;
One, two, three, four, six, eight, ten, big, dry, abundant, earth, scholar, China, field, you, you, Shen, mouth, sky, moon, wood, eye, forest, painting, umbrella, king, man, non-Philippines, sky.
2. Translation: When an object moves horizontally or vertically, and the direction of the object remains the same, this movement is translation. Only graphics with the same shape, size and direction can overlap each other through translation.
3. Rotation: The phenomenon that an object moves in a circle around a certain point or an axis is rotation.
Mathematics knowledge points in the second volume of the second grade of primary school (unit 4 ~ 6)
Unit 4: Division in Table (2) 1. Use the multiplication formula of 7, 8 and 9 to find the quotient.
Quotient method: think "divisor × () = dividend", and then calculate the quotient according to the multiplication formula.
Second, solve the problem.
Find out how many digits a number has, divide a number into several parts on average, and find out how many parts there are, all by division.
Unit 5: Mixed Calculation
First, hybrid computing
Mixed operation, multiply first, then divide, then add and subtract. If there are brackets, count them first. Only addition, subtraction, multiplication and division should be calculated from left to right.
Second, solve the practical problems of two-step calculation.
1, think about what problems to solve first, and then what problems to solve.
2, you can draw pictures to help analyze.
3. It can be distributed computing or integrated computing.
Unit 6: Division with remainder
First, divide by the remainder.
1 has the meaning of remainder division: when some objects are divided equally, sometimes there will be a remainder.
2. Relationship between remainder and divisor: In division with remainder, remainder must be less than divisor. The remainder of is less than the divisor 1, and the smallest remainder is 1.
3. Calculation method of pen division:
(1) Write the division number "Factory" first.
(2) The dividend is written in the divisor, and the divisor is written to the left of the divisor.
(3) Trial quotient, written on the dividend, the dividend-oriented unit.
(4) Write the product of quotient and divisor under the dividend, and the same digits should be aligned.
(5) Divider minus the product of quotient and divisor. If there is no remainder, it means divisibility.
4. The calculation method of remainder division can be divided into four steps: one quotient, two squares, three subtractions and four ratios.
(1) Quotient: Trial Quotient. If you want to multiply the divisor by a few, the nearest dividend is less than the dividend, then the quotient is a few, written on the unit of dividend.
(2) Multiplication: multiply the divisor and quotient, and write the number below the dividend.
(3) Subtraction: Subtract the product of quotient and divisor from the dividend, and write the difference below the horizontal line.
(4) Ratio: Compared with the divisor, the remainder must be small.
Second, solve the problem.
According to the meaning of division, to solve the simple division problem with remainder, we should deal with the remainder flexibly according to the actual situation.
Mathematics knowledge points in the second volume of the second grade of primary school (unit 7 ~ 9)
Unit 7: Understanding Numbers within 10,000 1. Understanding Numbers within 1000
1, 10, one hundred is one thousand.
2. When reading, read from a height. There are hundreds in a hundred, ten in ten, and a zero in the middle. No matter how many zeros there are in the end, you don't read them.
3. When writing numbers, you should start from the high position, with hundreds of digits, ten digits and ten digits. Any number without a number will be written as zero.
4. Composition of numbers: According to what number is on each number, it consists of several such counting units.
Second, the understanding of the number within 10000
1, 10 One thousand is ten thousand.
2. Numbers within 10,000 are the same as those within 1000.
3. The minimum two digits are 10, and the two digits of are 99; The minimum three digits are 100, and the three digits are 999; The smallest four digits are 1000, and the four digits are 9999; The smallest five digits are 10000, and the five digits of are 99999.
Three, the whole hundred, integer thousand addition and subtraction
Addition and subtraction methods of 1, integer hundred and integer thousand.
(1) Look at the whole hundred and the whole thousand, and then add and subtract.
(2) Add and subtract the number before 0, and then add the same number of zeros as integer hundred and integer thousand at the end of the obtained number.
Step 2 estimate
Think of a number as its approximation and then calculate it.
Unit 8: grams and kilograms
Grams and kilograms are international units of mass. When measuring the mass of lighter items, we usually use "gram"; When measuring the mass of heavier items, the unit is usually "kilogram".
1kg = 1000g， 1kg = 1kg， 1kg = 2kg， 1kg = 500g，
1 kg = 10 Liang, 1 Liang = 50g.
To estimate the weight of an item, we need to combine the size, texture and other factors of the item.
Unit 9: Mathematics Wide Angle
In reasoning, the inevitable situation is determined according to the conditions first, and then other situations are determined by the exclusion method.